Medically reviewed by Susan Kerrigan, MD and Marianne Madsen
Spinal muscular atrophy (SMA) is a rare genetic condition that leads to impaired muscle function starting in childhood. One in 11,000 babies are affected by the disease, which can be a severe detriment to one’s quality of life. Although treatments and therapeutic devices for SMA exist, they are often frustrating and burdensome for the patient and their family.
That’s why new advances in treatment are always welcome, such as a new gene replacement therapy trialled by researchers at Charité-Universitätsmedizin Berlin (Charity-University Medicine Berlin). The results of the study were published in The Lancet Child & Adolescent Health.
The study
With the goal of gauging the effectiveness of a gene therapy medication called onasemnogene abeparvoven (Zolgensma), a team of researchers recruited 76 children between the ages of six months and five years from 18 different treatment centers spanning across Germany and Austria. The children, who had been taking Zolgensma from September 2019 to November 2020, as well as another SMA drug, nusinersen, were monitored for a period of six months.
The team evaluated the participants’ motor function before and after treatment. After controlling for age, sex, disease type (there are several types of SMA), and any prior therapy, the researchers deemed the gene therapy to be effective at restoring muscle function.
“Gene replacement therapy improved significantly the children’s muscle strength, irrespective of whether they had received prior treatment with nusinersen. They were able to reach new developmental milestones and showed improvements in crawling, sitting and standing,” said Dr. Angela M. Kaindl, Head of the Department of Pediatric Neurology and Director of Charité’s Center for Chronically Sick Children.
Side effects
Gene therapies are not without their side effects, however. Previous SMA medications such as nusinersen had a wide range of adverse effects including respiratory and ear infections, scoliosis, stunted growth, and an increased risk for kidney damage. When observing the side effects of Zolgensma, the researchers found fever, vomiting, low blood platelet count, and liver inflammation to be among them.
Dr. Kaindl said these side effects could be mitigated, however, and that despite them, Zolgensma could be a safe alternative to nusinersen.
“…Liver function abnormalities occurred in six children. Most cases required prolonged corticosteroid therapy to reduce liver inflammation beyond the recommended treatment duration of eight weeks. However, adverse effects are easily managed with close clinical monitoring in a specialist center,” said Kaindl. “This new gene replacement therapy offers an effective and safe alternative to nusinersen, particularly if used early.”
As for any potential long-term side effects, the team is planning to extend the duration of their study in order to follow-up with the participants at a later date.
Although spinal muscular atrophy is a debilitating illness, albeit a rare one, advances in gene therapy are proving to be the future of treatment for the disease.
References
- Spinal Muscular Atrophy – Conditions | Children’s National
- Gene replacement therapy with onasemnogene abeparvovec in children with spinal muscular atrophy aged 24 months or younger and bodyweight up to 15 kg: an observational cohort study – ScienceDirect
- Gene Therapy Improves Muscle Function for Children With Spinal Muscular Atrophy